Stacks of material to be shipped, such as stacks of paper sheets for example, are often placed onto a support such as a pallet for shipping. Such stacks are typically tied onto the pallet using bands made of plastic or metal and which contribute to holding the stack together. It was common to place a sheet of wood on top of the stack prior to wrapping the stack with the bands. This was done for two reasons.
First, the rigidity of the wood helps prevent damage to the stacked material, and especially to the uppermost sheets thereof, which can be caused by the bands which are used to wrap the stack. With the sheet of wood in place, the bands are kept spaced apart from the uppermost portions of the stack, and the sheet of wood contributes to even out the pressure exerted by the bands onto a greater surface and reduce the occurrences of high pressure points on the stack.
Second, sometimes the stacks can include a number individual piles of materials. Because the tops of the individual piles are not linked to one another, they can tend to open up, and even fall in opposite directions during shipping. Using a sheet of wood as dunnage on top of two or more such piles, with the bands holding the sheet of wood down onto the piles, serves as a link between the tops of the piles and greatly reduces the possibility that the piles open up during shipping.
Although the use of wood sheets as stack-top dunnage was satisfactory to a certain degree, it did have some inconveniences, such as relatively high costs, weight, and cumbersomeness between uses. There thus remained room for improvement.